1. Field of the Invention
The present invention relates to an electronic projectile detonator.
2. Description of the Related Art
Modern electronic detonators currently employ for their energy supply either primary cells, or preferably batteries, which are mechanically/chemically activated only through great accelerations which occur when firing a projectile. This has the advantage that detonators thus equipped do not require maintenance with respect to replacement, for example, of an otherwise employed battery-primary cell, since these batteries are entirely passive during their storage and therefore, permit long storage times.
In the case of detonators thus equipped, in general, an operating sequence of a previously programmed detonator function is started through the activation of the battery, i.e., by running up the battery voltage during the mechanical/chemical activation through the launching accelerations.
The activatable batteries employed must therefore be layed out constructionally such that they reliably activate within an entire temperature range even with an extremely small propellant charge during the firing. On the other hand, the batteries must withstand mechanical loading through environmental tests (for example, a 1.5 m drop onto a steel plate) and acceleration during the charging process without activating. Therewith, by necessity, the constructionally required safety margins between activation and nonactivation grow small. In addition, individual faults in the battery, which are generated by defective battery fabrication or material faults, can reduce these safety reserves further.
In addition to the above statements, it also cannot be excluded that such batteries may activate before the shot. Depending on the function and safety layout of the detonator, this can possibly lead to dangerous detonator states during the overflight phase.
Specifically, in the event of use of artillery, one""s own troops are also overshot. For that reason, the requirements with respect to safety against too early a projectile breakup (overflight safety) are, in general, very high. Known numbers for the maximum permitted probability of a premature breakup are between 10xe2x88x925 and 10xe2x88x926.
On the other hand, due to the above described necessary small constructional gap between function and nonfunction of an acceleration-activatable battery (1.5 m drop no, smallest charging: yes) function problems must also be anticipated with small charging and can also be observed in practice.
In addition, the production of such special batteries due to today""s increasing corporate mergers has become concentrated on increasingly fewer companies such that the supply situation, not least through export restrictions of some countries for such products, is becoming increasingly more difficult. If, however, batteries are available, then, in general, only at prices which are often incompatible with the xe2x80x9clow-cost productxe2x80x9d detonator.
Other known methods of energy generation during the flight of a projectile are generators, installed in the detonator, which generate electric energy for electronics, either by piezo effect or electrodynamically by projectile acceleration, spin build-up or oncoming airstream. However, such solutions are, for example, for an artillery detonator, either not suitable due to the low energy yield (piezo) or even more expensive and more unreliable than a built-in battery. Furthermore, such solutions can only be obtained either as a special fabrication as a product of a long and expensive development phase or, with at least similar difficulty, as an acceleration-activatable battery.
Building on this prior art, it is therefore the task of the present invention to specify a new projectile detonator, specifically an artillery projectile detonator, which can operate without a battery or additional energy generation during the projectile flight.
It is proposed to employ a capacitor charged during the programming phase for operating the projectile detonator in the flight phase, the capacitor having a very low leakage current in order to be able to bridge a time in the range of minutes between the programming and the start of the flight phase, without significant energy loss.